The standard battery gauge deals in increments of 10%. What does that mean? It means if your battery is at 99% charge, it's likely the battery meter is rounding down to 90%, simply because it doesn't have the ability to display 99% or 98%, etc. I don't think it's all because of the way the phone charges. Just seemed like a logical reason. I'm not really sure why they designed it this way... Laptops can display battery %'s in increments of 1%... Lazy developers maybe?